首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12篇
  机械仪表   12篇
  2012年   1篇
  2011年   3篇
  2009年   4篇
  2006年   2篇
  2005年   1篇
  1998年   1篇
排序方式: 共有12条查询结果,搜索用时 93 毫秒
1.
Internal combustion engines have several vibration sources, such as combustion, fuel injection, piston slap and valve operation. For machine condition monitoring or design improvement purposes, it is necessary to separate the vibration signals caused by different sources and then analyse each of them individually. However, traditional frequency analysis techniques are not very useful due to overlap of the different sources over a wide frequency range. This paper attempts to separate the vibration sources, especially piston slap, by using blind source separation techniques with the intention of revealing the potential of the new technique for solving mechanical vibration problems. The BSS method and the Blind least mean square algorithm using Gray's variable norm as a measure of non-Gaussianity of the sources is briefly described and separation results for both simulated and measured data are presented and discussed.  相似文献
2.
Improving fuel efficiency with laser surface textured piston rings   总被引:4,自引:0,他引:4  
An experimental study is presented to evaluate the effect of partially laser surface textured piston rings on the fuel consumption and exhaust gas composition of a compression-ignition IC engine. Dynamometer tests were performed with a Ford Transit naturally aspirated 2500 cm3 engine at a wide range of engine speeds under near-half-load conditions. A comparison was made between the performance of reference non-textured conventional barrel-shaped rings and optimum partial laser surface texturing (LST) cylindrical-shape rings. It was found that the partial LST piston rings exhibited up to 4% lower fuel consumption, while no traceable change in the exhaust gas composition or smoke level was observed.  相似文献
3.
应用铁谱分析技术,通过对4105柴油机磨合试验中的产生的机油颗粒物进行分析,准确掌握内燃机的磨合状态和磨合进程,并以此为依据有效缩短了磨合时间,提高了磨合试验效率,同时也为内燃机的后续试验提供了有力的保障。  相似文献
4.
王虎 《机械》2006,33(12):5-6
应用铁谱分析技术,通过对4105柴油机磨合试验中的产生的机油颗粒物进行分析,准确掌握内燃机的磨合状态和磨合进程,并以此为依据有效缩短了磨合时间,提高了磨合试验效率,同时也为内燃机的后续试验提供了有力的保障。  相似文献
5.
Reverse Engineering is used to determine the inlet port geometry of a diesel engine. The case described illustrates a general problem where the precise nature of manufactured components relies heavily on the skills of pattern makers and foundrymen. Two methods are used, one in which the geometry is determined by used or silicon rubber moulding and one by machining planes off a cylinder head. In the latter case the geometry was measured by a contact probe on a CMM, generated in the CMM software files and transferred to Pro/ENGINEER® data files. The procedure, and the difficulties experienced with applying surface modelling to the generated data are described. General conclusions are drawn on the present state of reverse engineering as a means of adjusting CAD data to ensure conformance to specification.  相似文献
6.
以某四行程四缸内燃机为对象,在内燃机试验台架上进行多工况下的内燃机曲轴主轴承三维(即同时包括轴颈在轴承截面中的平面运动和轴线方向运动)轴心轨迹实际测量。轴颈在曲轴轴承中的位置采用电涡流传感器测量并通过后处理计算获得。结果表明,内燃机工作中,曲轴轴承轴颈存在沿轴线方向的运动;实际内燃机曲轴轴承的轴心轨迹为三维空间曲线;一个内燃机工作循环的曲轴轴承轴心轨迹曲线是不封闭曲线;曲轴轴承轴颈沿轴线方向存在较大的移动量,其数值大于轴承径向间隙;随内燃机转速和负荷增加,轴颈的轴向移动量增大;内燃机转速较低时,轴承轴颈的轴向运动在一个内燃机工作循环中的变化规律具有一定的周期性,变化周期数等于内燃机的气缸个数,而高转速情况下没有明显的变化规律性。  相似文献
7.
基于纳米技术,采用环保型的喷涂工艺,将减摩性能良好的固体润滑材料MoS2和碳石墨均匀并牢固地喷涂在内燃机滑动轴承的内工作表面,制备一种高性能复合涂层。摩擦学性能测试表明,具有无铅表面涂层的高性能内燃机轴瓦的承载能力和摩擦学性能均优于目前广泛应用的电镀轴瓦。  相似文献
8.
王楠  唐刚志  张力 《机械》2011,38(12):1-4
利用数值模拟对某汽油机的冷却水套进行了冷却性能研究,对原机冷却水套内冷却水的流场分布、冷却水套内壁面换热系数和压力损失进行了分析。计算结果表明:该汽油机冷却水套总体分布合理,设置的8个分水孔各自取到不同的作用;通过大孔B1、B2的流体用于冷却鼻梁区等重点区域,其它孔主要用来将绕流缸体的冷却水引入缸盖,对缸盖冷却起补充作用;鼻梁区等热负荷大的区域冷却水流速大于0.5m/s,达到了冷却要求,整个水套没有流动死区,避免了潜在的局部过热事故的发生。  相似文献
9.
废气再循环是一种简单有效的降低氮氧化物的方法。介绍了柴油机电控EGR的匹配与标定,探讨了空气系统的大闭环进气量控制和小闭环EGR阀位置控制方式。结果表明通过这种控制匹配方式能够比较好地实现空气系统的静态稳定性和动态跟随性,并能够满足柴油机欧IV排放对空气系统的要求。  相似文献
10.
随着内燃机动办性能和转速的不断提高,冷却散热问题越来越受到重视,因而对冷却风扇的研究有重要意义.高速旋转的冷却风扇,叶片受风力反作用后的变形对风扇的性能有很大的影响.利用商业软件SC/Tetra和ANSYS,把流场计算得到的叶片表面压力映射到结构分析中去,考虑流场与结构的相互作用,以流固耦合理论来分析叶片变形前后冷却风扇性能的改变.  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号